function misc_related_string_id($s)
{
$t = misc_get_keywords($s, 0);
// isalnum
$a = explode(' ', $t);
usort($a, 'misc_related_string_id_sort');
// fabricate 32bit id from 4 longest keywords
$id = 0;
for ($i = 0; isset($a[$i]) && $i < 4; $i++) {
$id <<= 8;
$id |= misc_crc8($a[$i]) & 0xff;
}
return $id & 4294967295.0;
}
<?php
function misc_crc8($s, $crc = 0)
{
$polynomial = 0x1070 << 3;
$len = strlen($s);
for ($i = 0; $i < $len; $i++) {
$crc ^= ord($s[$i]);
$crc <<= 8;
for ($j = 0; $j < 8; $j++) {
if (($crc & 0x8000) != 0) {
$crc ^= $polynomial;
}
$crc <<= 1;
}
$crc = $crc >> 8 & 0xff;
}
return $crc;
}
echo sprintf("%x", misc_crc8("test"));
